Difficult to say in 5 minutes. There is a lot of literature about ecology of Bembix, but impossible to summarize here in brief. In Israel, species may have 2 or more generations, but knowledge in S.Med. is sparse. Of course life cycle varies, depending from geografic region etc.

Thanks all for the commentsI spend many hours this weekend in searching and reading literature (open source in the web) about ecology of Bembix and the familystill some questions keep open

1. is adults Overwintering (in some spices)? or only prepupa do it (diapause)? 2. if adults do Overwintering, how many season they can keep (in they lucky)

I'm not writing academic post. just want to give some background knowledge about Bembix wasps and nature conservation in my blog attach to photos of Bembix in activeand this question related to the issue of nesting area conservation

As far as I know, prepupa (or imago in the cocon) is overwintering in German Bembix rostrata. Specimens appear in Mai and produce only one generation, which will appear in the next year. But we have a very short summer, compared with Israel, so I don't know what they are doing there.